Typical e-mail software permits a user to send and receive e-mail. Often, the e-mail system consists of an e-mail client that communicates with a server system. Where there is an e-mail client and an e-mail server, the e-mail server typically handles the interconnection to the Internet while the client communicates with the server to send and receive e-mails specific to the e-mail client user. A common name for the e-mail client software is a Mail User Agent or MUA. A typical user often includes contact information in the signature section of the body of an e-mail. When an MUA user receives an e-mail from a sender that is not in the address book of the receiving MUA user, the MUA receiving user may manually extract the sender's contact information from the body of the received e-mail (e.g., manually extract contact information from the signature block of the received e-mail) in order to manually add the sender's contact information to the receiver's address book. The decision on what contact information to include in the body of the e-mail is up to the sending user and may be changed in each e-mail created by the sending. Many MUA's provide a signature function which permits the sending user to automatically include a customizable signature that may also include certain contact information, such as the sending user's name, phone number, e-mail address, company name, and job title. If the sending user changes contact information, the receiving user must either be specifically notified by the sender that the information has changed and needs to be updated or the receiving user must notice that the information has changed and update the information in the address book accordingly.